Host objects

A host object is a logical object that represents a list of worldwide port names (WWPNs) and a list of iSCSI names that identify the interfaces that the host system uses to communicate with the Storwize® V3500 system. Fibre Channel and SAS connections use WWPNs to identify the host interfaces to the systems. iSCSI names can be either iSCSI qualified names (IQNs) or extended unique identifiers (EUIs).

A typical configuration has one host object for each host system that is attached to the system. If a cluster of hosts accesses the same storage, you can add host bus adapter (HBA) ports from several hosts to one host object to make a simpler configuration. A host object can have both WWPNs and iSCSI names.

The system does not automatically present volumes to the host system. You must map each volume to a particular host object to enable the volume to be accessed through the WWPNs or iSCSI names that are associated with the host object. For Fibre Channel and SAS-attached hosts, the system reports the node login count, which is the number of nodes that can detect each WWPN. If the count is less than expected for the current configuration, you might have a connectivity problem. For iSCSI-attached hosts, the number of logged-in nodes refers to iSCSI sessions that are created between hosts and nodes, and might be greater than the current number of nodes on the system.

When you create a new Fibre Channel host object, the system presents a list of candidate WWPNs that have logged into the system but are not yet configured in host objects. Some Fibre Channel HBA device drivers do not leave their ports logged in if no disks are detected on the fabric, so they are not visible in the list of candidate ports. You must enter the WWPNs for such hosts manually. There is no equivalent list of candidate IQNs available when creating iSCSI hosts. All iSCSI host port IQNs must be entered manually.

Note: You must not include a WWPN or an iSCSI name to the host that belongs to the system.

A WWPN or iSCSI name can be added to only one host object.